package servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ContextServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取web.xml中配置的上下文参数context-param
        ServletContext context = getServletConfig().getServletContext();
        String username = context.getInitParameter("username");
        String password = context.getInitParameter("password");
        System.out.println("context-param参数username的值是: " + username);
        System.out.println("context-param参数password的值是: " + password);
        //2.获取当前工程路径，格式：/工程路径
        System.out.println("当前工程路径: " + context.getContextPath());
        //3.获取当前工程部署在服务器硬盘上的绝对路径
        /*
        * / 斜杠表示被服务器解析地址为：http://ip:prot/工程名/   映射到IDEA代码的web目录
        * / 代表IDEA中web目录，获取web中文件的绝对路径就可以使用 /文件名
        * */
        System.out.println("当前工程绝对路径: " + context.getRealPath("/"));
        System.out.println("当前工程a.html的绝对路径: " + context.getRealPath("/a.html"));
    }
}
